Multicultural Healthy Diet to Reduce Cognitive Decline & Alzheimer Disease Risk We propose a randomized clinical trial to investigate whether the Multicultural Healthy Diet (MHD), an anti-Inflammatory diet based on the Dietary Inflammatory Index tailored to a multi- cultural population, can improve cognitive functioning in a middle aged (40-65 yr old) urban population in Bronx, New York compared to a usual diet. We propose this study starting in a middle-aged population because early indicators of cognitive aging may manifest long before old age. Many previous studies have also used global mental function tests and relied on designs with relatively few and widely spaced repeated measurements, both of which can compromise the ability to detect cognitive change. To overcome these limitations, we propose to assess dietary effects on cognition using a ?measurement-burst? design, which will consist of administering 35 brief assessments of a broad range of cognitive functions using smartphones during week-long measurement-bursts at nine-month intervals and repeated three times. This intensive measurement approach allows assessment of cognitive function in ?real-time? which can provide a more reliable index of function that is more sensitive to change. The aims of this proposal are to: A1. Show that the MHD can be adapted to a diverse middle-aged cohort in the Bronx. Evaluate pre- and post-intervention serum biomarkers indicative of a MHD diet pattern, specifically total folate & vitamers, tocopherols, carotenoids, vitamin B12 and fatty acid profile; and self-reported intake of food groups such as fruits and green leafy vegetables, to compare study arms. A2. Test whether a MHD intervention in a multi-ethnic urban setting can benefit cognitive function in a middle-aged population. Assess cognitive functions (spatial working memory, short term memory, self-reported mental sharpness, processing speed), using real-time ambulatory assessments over a 7-day period every 9 months to evaluate the time course over which positive impacts are detectable. A3. Identify components of the MHD diet that are associated with stable or improved measures of cognition. We will evaluate biomarkers indicative of a MHD diet pattern (see A1) and relate to cognitive function measures.